Electrohydraulic Transmission Controller Cooling Integration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional hydraulic systems with electrohydraulic transmission controllers are inefficient in reducing thermal stresses on switching elements in hybrid vehicle drive trains, requiring complex and costly cooling systems with additional coolant circulation and pumps.
Innovation Solution
An electrohydraulic transmission controller with electrically actuatable pressure control valves and valve arrangements that adjust cooling oil volume flows to strategically cool switching elements, integrating cooling into the existing hydraulic circulation without additional devices, reducing thermal stress effectively and economically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a separate cooling system with additional coolant circulation and pumps is used to cool switching elements, then thermal stress reduction is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines the cooling function with the existing hydraulic transmission system by using the transmission oil circulation system for both hydraulic control and cooling purposes. The oil pump serves dual functions: providing hydraulic pressure for valve operation and circulating coolant through the switching elements. This eliminates the need for separate cooling pumps and coolant circulation systems, thereby reducing device complexity while maintaining effective thermal stress reduction.
Solution Approach 2:
The transmission oil is given multiple functions: it serves as hydraulic fluid for actuating pressure control valves and simultaneously as coolant for switching elements. The oil circulation path is designed to pass through cooling channels in the switching elements, enabling the same fluid system to perform both hydraulic control and thermal management functions, thus avoiding additional system complexity.
2Temperature
If wet multi-plate clutches are used for cooling switching elements, then thermal stress reduction is improved, but weight and installation space increase
Solution Approach 1:
The cooling function is merged with the existing hydraulic transmission system by routing the transmission oil through cooling channels in the switching elements. This eliminates the need for separate cooling components such as wet multi-plate clutches, thereby reducing system weight while maintaining effective cooling of switching elements during operation.
3Device complexity
If conventional hydraulic systems are used without integrated cooling, then device simplicity is maintained, but thermal stress on switching elements increases
Solution Approach 1:
The patent integrates cooling functionality into the existing hydraulic system by using the transmission oil circulation path to also serve as a coolant flow path. Cooling channels are incorporated into the switching element structure, allowing the same oil that provides hydraulic pressure to also remove heat, thereby maintaining system simplicity while effectively reducing thermal stress.
Solution Approach 2:
The transmission oil continuously circulates through the system performing hydraulic functions, and this continuous circulation is leveraged to simultaneously provide continuous cooling of switching elements. The oil passes through cooling channels in the switching elements during its normal circulation cycle, ensuring ongoing thermal management without interrupting or adding to the hydraulic operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution simplifies and cost-effectively reduces thermal stresses on vehicle drive train assemblies across the entire operating range, integrating cooling into the transmission device with minimal constructive changes and reduced complexity, resulting in a more efficient and lightweight system.
Implementation Method 1
electrically actuatable pressure control valves and a plurality of valve arrangements that can be acted on respectively by a hydraulic control pressure subject to the control of the pressure valves
Implementation Method 2
a sub-assembly of a motor vehicle drive train can be acted on by a cooling oil volume flow that is subject to the control pressure of the additional valve arrangement
Implementation Method 3
the switching elements are usually wet multi-plate clutches of disc brakes, which are cooled by a cooling oil volume flow
Data Source
AI summary
An electrohydraulic transmission controller (7), a transmission device with an electrohydraulic transmission controller and a vehicle drive train that features an electrohydraulic transmission controller are disclosed. The electrohydraulic transmission controller is constructed with a plurality of electrically actuatable pressure control valves (9 to 16), as well as with a plurality of valve arrangements (17 to 34) that can be acted on in each case by an hydraulic precontrol pressure depending upon the actuation of the pressure valves, by way of which valve arrangements switching elements (A to E) of a transmission device can be acted on in each case with a control pressure to produce a required operating state of the transmission device. An additional pressure control valve (9) is provided to adjust a precontrol pressure (p_VS—9) of an additional valve arrangement (35), whereby downstream of the additional valve arrangement, the sub-assembly (6) of a vehicle drive train can be acted on by a cooling oil volume flow subject to the precontrol pressure of the additional valve arrangement and an operating state of the additional valve arrangement (35) corresponding to it.